The present invention is generally directed to a multiple viewer image viewing system capable of providing a plurality of images to viewers and/or a three dimensional (3D) visual effect in a viewed image.
With the advent of multiple player video arcade games it has been desirous to provide a system capable of presenting a plurality of 2D images to a plurality of viewers. Such a system could also be utilised in a number of other areas, for example in education and training. Currently such a system can only be achieved by supplying each of the viewers with their own display system which depicts the image to be seen by that viewer on a separate screen. It will be appreciated that the provision of multiple display systems is costly both in terms of money and real estate.
There have also been numerous attempts to produce, a system capable of producing a real 3D image which can be viewed by the naked eye, and preferably one that can be viewed by a plurality of viewers.
One of the present applicants prior attempts to provide an autostereoscopic display system resulted in that disclosed in Australian Patent Application No. 66718/94. This system did enable a viewer to see a stereoscopic image without the need for special glasses or the like. However, this system did have a number of limitations.
It has been found that the Applicants earlier system was practically only suitable for a single viewer. In order to maintain a 3D effect it is essential that the left and right eyes of the viewer see the respective left and right images of the stereoscopic image. This is required even when the position of the viewers eyes vary through movement of the viewer. The Applicants earlier system maintained the stereoscopic image by moving the semireflective mirror and projection system in response to detected movements of the viewer effectively resulting in the viewing apparatus being fixed with respect to the viewer. That is, in order to maintain the stereoscopic image for the viewer the screen, mirrors and projectors had to be moved. The requirement to maintain these elements in the correct orientation required expensive componentry in order to effect smooth movements to limit any distractions to the viewer, and also made it inherently difficult for more than a single viewer to use the system. In fact, as the semireflective mirror was required to be moved to maintain the stereoscopic effect for one viewer, it was practically impossible for that semireflective mirror orientation to be suitable for another viewer to see a stereoscopic image.
Further as the semireflective mirror was required to be continuously moved, it necessarily formed part of the viewing apparatus and was enclosed in such. Because the semireflective mirror was enclosed it meant that the semireflective mirror and screen size was also limited for practical reasons.
The Applicants earlier system also required that the viewer be located at a relatively fixed distance from the screen in order to work effectively. Whereas it is desirable to allow the viewer to view the image at varying distances from the screen. Further, because of the limited screen size the viewer was required to be within a meter of the screen for best effect further making the addition of multiple viewers difficult.
It is therefore an object of the present invention to provide a display system overcoming at least one of the above noted problems.
With this in mind there is provided a multiple viewer display system including at least one semi reflective mirror, a retroreflective screen, and a plurality of optical imaging means, each viewer being provided with a respective said optical imaging means, each optical imaging means including a projection means for projecting images along an optical path, a tracking means to determine the spatial position of a respective viewers eyes, and a focussing means to modify the optical path in response to movements of the respective viewer.
In order to provide a stereoscopic image the projection means may be adapted to project left and right eye images along the optical path. In this way the present invention may be adapted to provide an autostereoscopic display system.
The display system may also include a plurality of semi reflective mirrors, so that multiple viewers are not required to view an image through a single mirror. Although it will be appreciated that a single semi reflective mirror could be large enough to accommodate a plurality of viewers, in some instances it may be more practical to provide a plurality of semi reflective mirrors. Of course it is not necessary that the number of semi reflective mirrors equal the number of viewers, although such an arrangement may be preferred.
In another preferred embodiment the retroreflective screen would be located above the viewers, for example on the ceiling, as opposed to more conventional arrangements whereby the screen must be located in front of the viewers.
The display system of the present invention can provide an improved 3D image that is relatively cheaper and allows the viewers to be in variable locations. Further the present invention allows for multiple viewers to be using the same screen without necessarily viewing the same image. That is, one advantage of the multiviewer arrangement of the present invention is that multiple viewers need not see the same image, even though they are looking at the same screen. The ability to have a single screen depicting different images to different viewers is especially advantageous in the video game market.
Further, it is possible that the spatial position of one image on the screen may overlap with the spatial position of at least one other image on the screen, yet still enable each viewer to view their respective image without any substantial interference.
It will be appreciated that if the image seen by both the left and right eyes are the same, then the viewer will see a 2D image. Hence, the present invention can provide both 2D and 3D images, by either providing the same image to both eyes of a viewer, or alternatively providing left eye and right eye images to the respective left and right eyes of a viewer.